Cutting tool



June 11, 1%45. L sMlTH 2,401,979

CUTTING TOOL Filed Feb. 18, 1944 INVENTOR LAWSON A 4 SMITH ATI'ORNEY Patented June 11, 1946 UNITED STATES {PATENT OFFICE CUTTING TOOL Lawson A. Smith, Los Angeles, Calif., assignor to Robert H. Clark, Los Angeles, Calif.

Application February 18, 1944, Serial No. 522,901

6 Claims.

This invention has to do with a cutting tool and has particular reference to that type of .tool used in performing the operation commonly known as spot facing or counterboring.

In the manufacture of various machine parts or devices it is frequently desired to finish or machine a surface in the immediate vicinity of or around a hole or bore. Devices known as counterbores or spot facers are used for this purpose, it being common to provide such devices with pilots that enter the hole and with blades which act to cut the surface desired. A common difliculty encountered with such tools is that a burr is formed .at the point of joinder of the surface and hole with the result that the tool becomes stuck or fails to operate smoothly. With most tools of the general character referred to it is not at all uncommon for the pilots to become stuck causing considerable inconvenience and often damage.

It is an object of this invention to provide a tool that will effectively spot face or counterbore and which performs such operations without the formation of a burr such as to cause Sticking of the pilot or improper operation ofthe tool generally.

It is another object of my invention to provide a tool of the character mentioned embodying an improved arrangement and formation of cutter blades. By my invention I provide cutter blades which are carried by the body of the tool so that they can be adjusted to cut surfaces of various sizes and the cutting edges of the blades are disposed to have a most desirable cutting action.

Another object of the invention is to provide a tool of the character referred to in which the pilot is removable making it possible to provide the tool with pilots of various size in order to fit various holes.

Another object of the invention is to provide a tool of the character mentioned in which the pilot is formed of a head detachable from a stem so that a common stem can be employed and various heads can be used on the stem to accommodate holes of various sizes.

The various objects and features of my invention will be fully understood from the following detailed description of a typical preferred form and application of the invention, throughout cut invention embodies, generally, a body H], a shank H on the body for mounting it in a machine of suitable character, blades l2 carried by the body to project from the lower end thereof, means 13 operable to clamp the blades in the desired position on the body, a pilot l4 carried by the body to project from the lower end thereof and to cooperate with the blades 12, and, means I5 for retaining the pilot on the body.

The body In is preferably an elongate element proportionedto firmly carry the blades l2, to carry the means 13 and to carry the pilot M. In the preferred form ofthe invention the body is hexagonal in cross-sectional configuration, as is shown throughout the drawing.

The shank H is preferably formed integral with the body 10 to project from the upper end thereof and is proportioned, shaped and finished to be accommodated in a suitable machine. In accordance with common machine shop practice I have shown a tapered shank, round in cross section and provided with a flattened part It at its upper end, I

The invention provides one or more blades I2 to be carried by the body It to project from the lower end thereof, the lower end portion of each blade being dressed or sharpened to have the dewhich description reference is made to the accompanying drawing, in which: Y i

Fig. 1 is a sideelevation of a tool embodying the present invention, being a view taken ;in a

direction to show the forward or leading side of Fig. 2 is a view similar to Fig. 1 taken with the tool rotated one of the blades of the tool.

sired cutting action. In the preferred form of the invention the lower end I! of the body In is flat 0t lie in a plane transverse of the longitudinal axis of the tool, and the cutters are carried by the body to project from the lower end of the body.

It is preferred, in practice, to provide the tool with two blades l2 and to locate them diametrically opposite each other or in opposite sides of the body H) in the general arrangement shown throughout the drawing. The body II! has channels 18 cut in diametrically opposite sides to carry the blades I2, the channels being made sufliciently wide to slidably pass the blades and being made sufliciently deep so that the blades are Well seated in the body to be firmly supported therein. By making the channels fairly deep the bottoms IQ of the channels are considerably wider or of greater area than they would be if the channels were shallow, this being due to the fact that the body is hexagonal in. cross section and the surfaces l9 become wider as the channels are made deeper.

In accordance with the preferred form of my invention I pitch or incline the channels l8 so the blades are carried to extend downwardly and outwardly from the lower end I! of the body. It is to be understood that the channels are pitched to correspond to each other so that the blades are carried at corresponding angles and that the angles are such that the channels extend a considerable distance upwardly in the body from the lower end to give the blades ample support.

The lower end portion of each blade is dressed to be understood that if a special configuration is g desired the edges 20 or the ends of the blades can be dressed accordingly. It is to be notedfrom the drawing that the blades are dressed so that the cutting edges 20 are at their forward 'or outer parts so that as forces are applied in the course of operation they are transmitted through the blades onto the bottoms 19 of the channels l8. Suitable clearance may be provided behind the edges 26 at the bottom of the cutters. It is also to be noted from Fig. 3 of the drawing that the arrangement which I have provided cause-s the edgesZB to be disposed tangent to a circle concentric with the axis of the tool rather than being radial relative to the axis of the tool. By thus locating the edges 20 I obtain a desirable cutting angle. front face 2P of each blade can be dressed or shaped so that theedge 20 has the proper angle relative to the work and: so that there is proper chip clearance as work progresses. In the case of a blade dressed for spot facing it is also desirable that the outer tip 21 be finished so that it is substantially perpendicular as shown in the drawing. s i

The means l3 provided for holding the blades in place in the channels I8 of the body may be any suitable means that will serve this function. In the preferred construction Iemp-loy a clamp plate 25 to engage the outer sides of each blade l2 and I employ a cap screw 26 to extend through the plate to thread onto the body adjacent the channel which carries the blade. The plate 25 is preferably a washer-like element. In the form of construction illustrated in the drawing the channels i8 are rather deep in the sides of the body and, therefore, the body is countersunk at 21 to accommodate the plates 25, the countersinks being made deep enough so that the plates 25 have bearing engagement on the outer surfaces of the blades l2. By using ordinary cap screws 26 as the means for clamping the plates 25 against the cutters the tool'can be adjusted by the use of an ordinary wrench thus making it simple and convenient to handle.

The pilot l4 includes a head 31] projecting below the lower end I! of the body from. a point above the edges 20 of the blades to a point a considerable distance beyond the blades. The head 36 is made long enough to give an efiective bearing in the hole in which the tool isoperated. In practice the head is turned and finished to work in the hole or bore with sliding clearance and thus operates as a pilot or steadying device for the entire tool.

A feature of the present invention is the pro vision of recesses 3| in opposite sides of the head 30 of the pilot M to receive the lower or projecting end portions of the blades I2, so that the cutting edges 20 of the blades overlap or extend inwardly into the recesses. The head 30 isturned uniformly from one end to the other or from a point above the edges 20 to the lower end of the headso that during operation of the tool the head occupies the upper end portion of the hole in which the tool is operated and acts to iron out or remove any burr that might tend to form at the junction of the hole and the plane of cut of the edges 20. The relationship of the cutting It is to be understood, of course, that the p edges 20, the head 30 and the notches 3| in the head will be apparent. from an examination of the drawing. I I l.

The head 38 of the pilot may be secured to the lower end of the body H! in any suitable manner. In the preferred construction a stem 35 is provided for this purpose and the head 39 is made detachable from the stern. In the construction shown the head as has a central bore 36 which receives the lower end portion of the stem and a i-suitableset screw 31 is provided for locking the headon the stern. The stem projects upwardly from the head 39 to slidably fit into a socket 38 formed centrallyin the body It from thelower end II. A set screw 39 is carried by the body to be operated into engagement with the stem '38 to hold it in the body. 'With the construction just described the pilot-can be completely de-g tached from the body at will and heads of various sizes can be installed on the stem as desired. It is to be-understood, of course, that each head employed is notched at 3] so that the cutting edges overlap the outer or finished face of the head so the tool operates without establishing an undesirable burr.

and application of my invention I do not wish to be limited orrestricted to the specific details herein set forth, but wish to reserve tomyseli to those skilledin the art and fall within the scope of the following claims. Having described my invention, I -claim:

1. In a rotary cutting tool, an elongate central body having a shank at one ,end and haying an angularly disposed channel in oneside. with a bottom in a plane tangent and parallelto the body and pitched to extend lengthwise and si'de wise of the body to open at the other endof-the body, a fiat elongate cutter in the channelj wi'th its inner side seated radially inward against 'the bottom of the channel and having an outerehd portion projecting from said 'othe'r endof' the body, which end portion has a cutting edge eX tending side'wise of g the body and substantially normally-to the longitudinal axis o'fthe body. mean-sretaining the cutter in the channel, the body having a central socket entering it ;f rom its said other end,- a pin upported in the socket cutter and projecting upward from thelow'er portion andbearing against the said other end-ofthe body to be spaced from the cutting edge-and 1 having curvedsideginthe plane of theoutersur face of the lower portion.

2, In a rotary clitti n gteolfan e1ong' at centmr body havinga shank at one" end ahdhavi ng two diametrically opposite side channelsfiiifthe bodyj the channels being angularly disposed and pitched in opposite directions and having bottoms in'pai'- allel planes tangent and parallel to the body and each pitched to extend-lengthwise and sidewise of the body to open at tlig-z otherv end oftliebo'dy:

' a flat elongate cutter} l3aQh Ha?1 n witih fit inner side seated radially inward against the bot- I-Iaving described only a typical preferred form.

any variations o'r' modifications that, may'appear v with an outer portion projecting beyond said other. end of the body, a set screw retaining thepimin tom of the channel and having an outer end portion projecting from said other end of the body, which end portion has a cutting edge extending sidewise of the body and substantially normal to the longitudinal axis of the body, means retaining the cutters in the channels, the body having a central socket entering it from its said other end, a pin held in the socket, and a pilot head carried by the pin having a lower portion spaced below the cutting edge and round in cross section with the plane of its outer surface intersecting the path of the cutting edge and also having an upper portion of reduced width to accommodate the cutters and projecting upward from the lower portion and bearing against the said other end of the body to be spaced from the cutting edge and having curved sides in the plane of the outer surface of the lower portion.

3. In a rotary cutting tool, an elongate central body having a shank at one nd and having two diametrically opposite side channels in the body, the channels being angularly disposed and pitched in opposite directions and having bottoms in parallel plane's tangent and parallel to the body and each pitched to extend lengthwise and sidewise of the body to open at the other end of the body, a flat elongate cutter in each channel with its inner side seated radially inward against the bottom of the channel and having an outer end portion projecting from said other end of the body, which end portion has a cutting edge extending sidewise of the body and substantially normal to the longitudinal aXiS of the body, means retailiing the cutter in the channels, the body having a central socket entering it from its said other end, a pin held in the socket, and a pilot head carried by the pin having a lower portion spaced below the cutting edge and round in cross section with the plane of its outer surface intersecting the path of the cutting edge and also having an upper portion of reduced width to accommodate the cutters and projecting upward from the lower portion and bearing against the said other end of the body to be spaced from the cutting edge and having curved sides in the plane of the outer surface of the lower portion, the bottoms of the channel being tangent to the socket in the body.

4. In a rotary cutting tool, an elongate central body having a, shank at one end and having an angularly disposed channel in one side with a bottom in a plane tangent and parallel to the body and pitched to extend lengthwise and sidewise of the body to open at the other end of the body, a fiat elongate cutter in the channel with its inner side seated radially inward against the bottom of the channel and having an outer end portion projecting from said other end of the body, which end portion has a cutting edge extending sidewise of the body and substantially normal to the longitudinal axis of the body, means retaining the cutter in the channel including a clamp member engaged in a transverse opening removed from the channel toward the first mentioned end of the body, the body having a central socket entering it from its said other end, a pin supported in the socket with an outer portion projecting beyond said other end of the body, a set screw retaining the pin in the socket, a pilot head carried on the outer portion of the pin, and a. set screw carried by the head engaging the pin to retain the head thereon, the head having a lower portion spaced below the cutting edge and round in cross section with the plane of its outer surface intersecting the path of the cutting edge and also having an upper portion of reduced width to accommodate the cutter and projecting upward from the lower portion and bearing against the said other end of the body to be spaced from the cutting edge and having curved sides in the plane of the outer surface of the lower portion.

5. In a rotary cutting tool, an elongate central body having a shank at one end and having two diametrically opposite side channels in the body, the channels being angularly disposed and pitched in opposite directions and having bottoms in parallel planes tangent and parallel to the body and each pitched to extend lengthwise and sidewise of the body to open at the other end of the body, a flat elongate cutter in each channel with its inner side seated radially inward against the bottom of the channel and having an outer end portion projecting from said other end of the body, which end portion has a cutting edge extending sidewise of the body and substantially normal to the longitudinal axis of the body, means retaining the cutters in the channels including separate clamp members engaging the cutters and carried in diametrically disposed transverse openings in the body between the channels and the first mentioned end of the body, the body having a central socket entering it from its said other end, a pin held in the socket, and a pilot head carried by the pin having a lower portion spaced below the cutting edge and round in cross section with the plane of its outer surface intersecting the path of the cutting edge and also having an upper portion of reduced width to accommodate the cutters and projecting upward from the lower portion and bearing against the said other end of the body to be spaced from the cutting edge and having curved sides in the plane of the outer surface of the lower portion.

6. In a rotary cutting tool, an elongate central body having a shank at one end and having two diametrically opposite side channels in the body, the channels being angularly disposed and pitched in opposite directions and having bottoms in parallel planes tangent and parallel to the body and each pitched to extend lengthwise and sidewise of the body to open at the other end of the body, a fiat elongate cutter in each channel with its inner side sea-ted radially inward against the bottom of the channel and having an outer end portion projecting from said other end of the body, which end portion has a cutting edge extending sidewise of the body and substantially normal to the longitudinal axis of the body, means retaining the cutters in the channels including separate clamp members engaging the cutters and carried in diametrically disposed transverse openings in the body between the channels and the first mentioned end of the body, the body having a central socket entering it from its said other end, a pin held in the socket, and a pilot head carried by the pin having a lower portion spaced below the cutting edge and round in cross section with the plane of its outer surface intersecting the path of the cutting edge and also having an upper portion of reduced width to accommodate the cutters and projecting upward from the lower portion and bearing against the said other end of the body to be spaced from the cutting edge and having curved sides in the plane of the outer surface of the lower portion, the bottoms of the channels being tangent to the socket in the body.

LAWSON A. SMITH. 

